You are a serious student of calculus in need of some tutoring support. A bit of research provides you with four possible tutors, all equally qualified, whom you ask for bids for their tutoring service.

Bob $15.00 per hour

Mary $12.00 per hour

Sean $10.00 per hour

Lee $8.00 per hour

Would you expect their bids to be the same? Why or why not?

It is not unreasonable to assume that the four individual tutors had different costs of production, that is, they had to sacrifice or give up different things.

Does a person with small children have a different opportunity cost than someone without small children?

Aside: Is this an issue in the income gender gap?